Alternate copolymer of butadiene and acrylonitrile and a process for preparation thereof

ABSTRACT

ALTERNATE COPOLYMER OF BUTADIENE AND ACRYLONITRILE WHICH IS A NOVEL PRODUCT AND A PROCESS FOR PREPARATION THEREOF WHICH COMPRISES CONTACTING A MIXTURE OF BUTADIENE AND ACRYLONITRILE IN LIQUID PHASE WITH THE CATALYST SYSTEM FORMED BY MIXING VANADIUM (V) OXYCHLORIDE OR CHROMIUM (VI) OXYCHLORIDE WITH A TRIALKYLALUMINUM COMPOUND.

P 25, 1972 AKIHIRO KAWASAKI ETAL 3,658,775

ALTERNATE COPOLYMER OF BUTnDIENE AND ACHYLONITRILE AM) A PROCESS FORPREPARATION THEREOF Filed June 26, 1969 2.5,- 5 7 IO l5 A WAVE NUMBERCM" United States Patent ALTERNATE COPOLYMER OF BUTADIENE ANDACRYLONITRILE AND A PROCESS FOR PREP- ARATION THEREOF Akihiro Kawasaki,Masanobu Tanrguchr, and Tsuneto Nishiyama, Chiba-ken, Japan, assignorsto Maruzeu Petrochemical Co., Tokyo, Japan Filed June 26, 1969, Ser. No.836,736 Int. CI. 00811 1/14, 3/02 US. Cl. 260-825 9 Claims ABSTRACT OFTHE DISCLOSURE Alternate copolymer of butadiene and acrylonitrile whichis a novel product and a process for preparation therof which comprisescontacting a mixture of butadiene and acrylonitrile in liquid phase withthe catalyst system formed by mixing vanadium (V) oxychloride orchromium (VI) oxychloride with a trialkylaluminum compound.

BACKGROUND OF THE INVENTION Field of the invention Description of theprior art As far as the inventors know, there is no prior art inconnection with the alternate copolymer of butadiene and acrylonitrileand the process for preparation thereof.

DESCRIPTION OF THE INVENTION In accordance with this invention, it hasbeen discovered that by using a catalyst system formed by mixingvanadium (V) oxychloride or chromium (VI) oxychloride with atrialkylaluminum compound within a given molar ratio, acrylonitrile canbe copolymerized with butadiene to produce a new and high molecularweight copolymer.

The composition of the copolymer according to elementary analysissubstantially agrees with the calculated value for a 1:1 copolymer ofbutadiene and acrylonitrile. The copolymerization reaction gave 1:1copolymer over a wide range of initial monomer composition and alsoindependently of polymerization time. The microstructure of thebutadiene unit in the copolymer was all trans-configuration. The NMRspectrum of the copolymer was shown to be very different from that ofthe conventional ultra high nitrile (acrylonitrile content 48 molepercent) random copolymer of butadiene and acrylonitrile prepared by theprior art. Two strong peaks were observed at 7.711 and 7.897 in the NMRspectrum of the conventional ultra high nitrile random copolymer. On theother hand in the NMR spectrum of the copolymer in this invention onlyone strong peak appeared at 7.711- in this region. This means that blocksequence of butadiene-butadiene is not substantially included.Consequently, each fact mentioned above supports the assumption that thepresent copolymer should be an alternate copolymer of butadiene andacrylonitrile.

The alternate copolymer is easily soluble in chloro- Patented Apr. 25,1972 form, acetone and dimethylformamide at room temperature. This newalternate copolymer has many advantageous properties. For example, itshows higher rubbery elasticity than the conventional ultra high nitrile(acrylonitrile content 48 mole percent) random copolymer and its glasstransition temperature is lower than that of the conventional copolymer.The microstructure of the butadiene unit in the conventional ultra highnitrile random copolymer is substantially composed of transand 1,2-configurations. On the other hand, as described above the microstructureof the butadiene unit in this alternate copolymer is alltrans-configuration.

The trialkylaluminum compounds which form one component of the catalystof this invention may be defined by the formula AlR R R wherein R R and-R are alkyl radicals having from 1 to 12 carbon atoms. The preferredtrialkylaluminum compounds, such as triethylaluminum ortriisobutylaluminum, are readily available through normal commercialchannels. Vanadium (V) oxychloride and chromium (VI) oxychloride areutilized in the purified form. The catalyst is simply prepared by mixingthe two components in a hydrocarbon or a chlorinated hydrocarbon diluentor in a mixture of them under air-free condition at low temperature. Thequantity of the two components may be varied over a wide range. In thepreferred embodiment the molar ratio of a trialkylaluminum compound tovanadium (V) oxychloride should be lower than 1.5

MEIR-2R3 vool3 In the preferred embodiment the molar ratio oftrialkylaluminum compound to chromium (VI) oxychloride should also belower than 1.5

AlR R R Hydrocarbons, such as heptane, octane, isooctane, benzene,toluene, etc.; chlorinated hydrocarbons, such as methylene chloride,ethylene chloride, tetrachloroethane, tetrachloroethylene,ethylchloride, trichloroethylene, trichloroethane, etc.; or a mixture ofsuch diluents are used as diluent in preparing the catalyst. The diluentshould be pretreated to remove harmful impurities which may he oftencontained therein. The presence of moisture, sulphur, sulphur-containingcompounds and oxygen would act as harmful impurities. In actualpractice, it is preferred that such impurities should not be presenteither in the diluent or in the monomer which is to be copolymerized.

The preparation of the new alternate copolymer of butadiene andacrylonitrile is carried out by contacting a mixture of the monomers inliquid phase with the catalyst system described above. Thecopolymerization reaction is generally carried out in the presence of aliquid organic diluent. Suitable diluents that can be used for thecopolymerization are hydrocarbons, such as heptane, octane, isoocta'ne,benzene, toluene, etc.; chlorinated hydrocarbons, such as methylenechloride, ethylene chloride, tetrachloroethane, tetrachloroethylene,ethylchloride, trichloroethylene trichloroethane, etc.; or a mixture ofsuch diluents. The diluent should also be pretreated to remove harmfulimpurities which may be contained therein.

The temperature of the copolymerization process can be varied over awide range, generally from 100 C. to +60 C. and preferably from -78 C.to +40 C. Sufficient pressure is employed to keep the monomers in liquidcondition regardless of whether a diluent is present in the reactionmixture or not.

In general, the molar ratio of butadiene to acrylonitrile in the initialmonomer composition will be from 20:80 to 80:20 and more usually will be50:50.

The activity of the catalyst in a diluent composed of hydrocarbon andchlorinated hydrocarbon or in a chlorinated hydrocarbon diluent issuperior to that of the catalyst in a hydrocarbon diluent. The yield ofthe alternate copolymer is higher than that of the copolymer prepared ina hydrocarbon diluent. Moreover, the glass transition temperature of thealternate copolymer prepared in a mixture of hydrocarbon and chlorinatedhydrocarbon or in a. chlorinated hydrocarbon diluent ,is lower than thatof the copolymer prepared in a hydrocarbon diluent. It is noteworthy tolower the glass transition temperature of the copolymer.

After the polymerization is complete, the reaction product is separatedfrom the reaction tube and treated to oxychloride, l millilitertriethylaluminum solution in toluene (1 molar solution), 3.3 millilitersacrylonitrile and 4.0 milliliters liquid butadiene were put successivelyin a 25 milliliter glass bottle held in a low temperature bath at 78 C.Thereafter the bottle was sealed and the acrylonitrile and butadienewere allowed to copolymerize at 35 C. for 16 hours. 0.10 g. of rubberyhigh molecular weight copolymer was obtained. From its elementaryanalysis and NMR spectrum the polymer was determined to be an alternatecopolymer of butadiene and acrylonitrile. The microstructure of abutadiene unit in the alternate copolymer was trans-configuration. Itsglass transition temperature was observed to be 26 C. and its intrinsicviscosity was 0.5 (dL/g.) in chloroseparate the diluent and unreactedmonomer. The alterform at 30 C. nate copolymer is then treated to removethe catalyst EXAMPLES 3-7 residues, which treatment may comprise washingwith In these exam ples, the usual, dry, alr-free technique f i q i gwlfilch g g g was employed and varying amounts of diluent, 1 molar me amIs a mmera acl sue as y roe one ac}. vanadium (V) oxychloride solutionin methylene chloride Thereafter the alteimate copolymer e be Washedwlth and 1 molar triethylaluminum or triisobutylaluminum glethanol Tfmiles gi be g vacuum solution in toluene were put successively intomilliy Sma l s o u lene 9 q may liter glass bottles held in a lowtemperature bath at be involved 1n the reaction product; this is easilyre- 7 C The amounts of diluent and cach solution of g i 332i dlethzl dt. d individual catalyst component are set forth in Table 1 FIG 5 tspecr 5 1 an 25 in milliliters. After the addition of the catalyst, 3.3millifi e Spelc g no R t liters acrylonitrile and 4.0 milliliters liquidbutadiene e o owmg elfamp es 1 us e new ema e were put successively intothe bottles, also employing copolymer butadlene 2 acrylommle a Processthe usual, dry, air-free technique at 78 C, Thereafter f preparatlonthereof m accordance wlth thls mven' these bottles were sealed and theacrylonitrile and bu- EXAMPLE 1 tadiene were allowed to copolymerize atthe various temperatures listed in Table 1 for 16 hours. From theirEmploying the usual, dry, air-free technique, 2 millielementary analysesand NMR spectra the copolymers liters methylene chloride, 10 millimolesvanadium (V) prepared in these examples were all identified as alteroxchloride, 1 milliliter trithylaluminum solution in nate copolymers ofbutadiene and acrylonitrile. The

y n a u u I toluene (1 molar solution (3.3 milliliters acrylomtnlemicrostructure of the butadiene umts in these alternate and millilitersliquid butadiene were put successively copolymers was alltrans-configuration.

TABLE 1 Monomers D11 t Catalysts Reaction conditions copolymer n ExampleA BD cH i lz V0013 Amman; Temp. Time Yield [1,] Ta number (1111.) (mL)(mL) soln.(ml.) soln. 0.) (hr.) (g.) (dl./g.) C.)

0 3 Et; 1 35 16 2.10 0.3 25 1 2 AlEta 1 35 16 1.96 0.3 20 1 2 .AlEt; 115 16 1.45 0.8 17 1 2 AliBus 1 35 10 2.03 0.3 20 0 3 AliBua 1 15 160.68-":

1 AN=Aerylonitrile; BD=Liquid butadiene.

I V001; so1n.=1 molar vanadium (V) oxychloride solution in methylenechloride; AlRi B2B: soln.=1 molar triethylaluminum ortriisobutylaluminum solution in toluene.

3 lnl=Intrinsie viscosity in chloroform at 30 0.; TB: Glass transitiontemperature measured by Perkin Elmer Difierential Scanning Calorimeter.

in a 25 milliliter glass bottle held in a low temperature bath at 78 C.Thereafter the bottle was sealed and the acrylonitrile and butadienewere allowed to copolymerize at 35 C. for 16 hours. 0.50 g. of rubberyhigh molecular weight copolymer was obtained. The result of theelementary analysis of the polymer is as follows: N .calculated value,13.1% by weight; observed value, 12.8% by weight.

The above mentioned values correspond to those of a 1:1 copolymer ofbutadiene and acrylonitrile. The alternate structure of the product wasconfirmed from the NMR data (FIG. 1), which show 7.7T peak arising frommethylene group in a butadiene-acrylonitrile sequence but no 7.9T peakarising from a butadiene-butadiene sequence. The microstructure ofbutadiene units was found to be all trans-1.4 configuration from IRanalysis (FIG. 2). Its glass transition temperature was observed to be28 C. and its intrinsic viscosity was 0.5 (dl./ g.) in chloroform at 30C.

EXAMPLE 2 Employing the usual, dry, air-free technique, 1 millilitermethylene chloride, 20 millimoles vanadium (V) EXAMPLES 8-12 In theseexamples, employing the usual, dry, air-free technique, varying amountsof diluent, 1 molar vanadium (V) oxychloride solution in toluene and 1molar triethylaluminum or triisobutylaluminum solution in toluene wereput successively into 25 milliliters glass bottles held in a lowtemperature bath at 78 C. The amounts of diluent and of each solution ofindividual catalyst component are set forth in Table 2 in milliliters.After the addition of catalyst, 3.3 milliliters acrylonitrile and 4.0milliliters liquid butadiene were put successively into the bottles alsoemploying the usual, dry, air-free technique at 78 C. Thereafter thesebottles were sealed and the acrylonitrile and butadiene were allowed tocopolymerize at the various temperatures listed in Table 2 for 16 hours.From their elementary analyses and NMR spectra the copolymers preparedin these examples were all deter mined to be alternate copolymers ofbutadiene and acrylonitrile. The microstructure of butadiene units inthese alternate copolymers was all transconfiguration.

TABLE 2 w Duuent Catalysts 3 Reaction conditions Copolymer 3 Example ANBD toluene V0013 Armani; Tom

p. Time Yield T (ml.) soln. (ml.) soln. Ml. C (hr.) (g) (dug; C

1 2 Et; 1 35 16 l. '0 4 1 2 AlE a 1 -15 16 1.52 03 ie 0 3 AlEte 1 --1516 1. 37 -17 1 2 111 1511; 1 a5 16 0.23 0 3 AhBtL-l l 16 0. 58 O. 5

; igafrcrlynloniltrile;1 BD =Ltdquid butadiene.l

so mo ar vana ium ox ch orlde solut' l butgmuminum o1ufion i toluene. 171011111 150 119118, A RiRzRs soln. 1 molar tnethylaluminum ortrnsosmgiggiatfihisrrlcegscosity in chloroform at 30 0.; TG=G1asstransition temperature measured by Perkin Elmer Difierential EXAMPLES1315 mium (VI) oxychloride solution in methylene chloride In theseexamples employing the usual dry aipfree 15 were put successively into25 milliliter glass bottles at technique varying amounts f diluent 053molar vana 25 C. Thereafter the bottles were held in a low temdium (V)oxychloride solution in toluene and 1 molar Perature bath at T f Varyingamounts of 1 i h l l i Solution in toluene were put Succes molartriethylalummum or trnsobutylaluminum solution i 1 i 25 milliliter glassbottles held in a low term in toluene, 5.3 milliliters acrylonitrile and4.0 milliliters perature h at 7g The amounts of diluent and llqllldbutadlene were put successively into the bottles, by

each solution of individual catalyst component are set employing theuslfalt air-free teChIlique at forth i T l 3 i i11 1i After the additionf the The amount of diluent and each solution of individual catalyst,3.3 milliliters acrylonitrile and 4.0 milliliters catalyst component areSet forth in Table 4 in millilitersliquid but di w put successively i hb l Thereafter the bottles were sealed and the acrylonitrile alsoemplq'ying th u l, dry, air-free t h i at and butadiene were allowed tocopolymerize at 35 C. -78 C. Thereafter these bottles were sealed andthe f 16 hours- From their elementary analyses and NMR acrylonitrile andbutadiene were allowed to copolymerize spectra the copolymers preparedin these examples were at the various temperatures listed in Table 3 f r20 all identified to be alternate copolymers of butadiene and hours.From their elementary analyses and NMR m acrylonitrile. Themicrostructure of the butadiene units in spectra, the copolymersprepared in these examples wer these alternate copolymers was alltrans-configuration.

TABLE 4 Monomers 1 D1 t Catalysts 1 Reaction conditions Copolymer 5 1uen Example AN BD CHlCle CrOlCh AlRiRzRa Temp. Time Yield TG number(ml.) (ml.) (ml.) soln. (ml.) soln. Ml. C.) (hr.) (g.) (dL/g.) C.) 3.34.0 2 1 AlEta 1 35 16 0.41 0.2 27 3. 3 4.0 1 2 AlEt; 1 35 16 O. 99 0. 63 3 4.0 1 2 AliBua 1 35 16 0.89 0.5

AN=Acrylonitrile; BD=Liquid butadiene. ClOzClz soln.=1 molar chromium(VI) oxychloride solution in methylene chloride; AlRlRdRB soln.=1 molartrlethylalumlnum or triisobutylalumlnum solution in toluene.

n1=Intrlnsic viscosity in chloroform at 30 C; T =Glass transitiontemperature measured by Perkin Elmer Differential Scanning Calorimeter.all identified to be alternate copolymers of butadiene and EXAMPLES20-24 acrylonitrile. The microstructure of butadiene units in thesealternate copolymers were all transconfiguration. 5 In these exampemploying the usual, y, air-free TABLE 3 Mononilers 1 Catalysts 2Reaction conditions Copolymer D uent Example AN BD toluene V00] 3 AlEt 9Temp Time Yield 1] number (ml.) (ml.) (ml.) soln. (ml.) soln. (ml.) 0-)J -l 3.3 4.0 2 1. 5 0.5 20 1.12 0.4 3. 3 4. 0 2 l. 5 0.5 20 0. 39 0. 8 33 4. 0 2 2. 5 0.5 -30 20 0.24 0.7

1 AN=Acrylonitrile; BD=Liquid butadiene.

2 V0013 soln.=0.63 molar vanadium (V) oxychloride solution in toluene;AlEt soln.=1 molar methyl-aluminum solution in toluene.

3 [1 ]=Intrlnsic viscosity in chloroform at 30 C.

EXAMPLE 16 technique varying amounts of diluent and 1 molar chro- VI)oxychloride solution in n-heptane were put Employing the usual dry,air-free technique 1 1111111- mlum successively mto 25 rmlllliterbottles at 25 C. Thereafter liter tetrachloroethylene, 2 mlllilitersvanadium (V) oxy the bottles were held in a low temperature bath at 78chloride solution in tetrachloroethylene (1 molar solution), 1milliliter triethylaluminum solution in toluene and Varymg amounts of 1molar tl'lethylalumlmlm (1 molar solution), 3.3 millilitersacrylonitrile, and 4.0 triisobutylaluminnm solution in toluene, 3.3milliliters milliliters liquid butadiene were put successively into aacrylonitrile and 4.0 milliliters liquid butadiene were put 25milliliter glass bottle held in a low temperature bath successively intothe bottles also employing the usual, at Thereaftef the bottle wassealed dry, air-free technique at 78 C. The amounts of diluentacrykimmle and butadiene were allowed to copqiymenze and each solutionof individual catalyst component are at 35 C. for 16 hours. 1.72 g. ofrubbery copolymer tf th T bl 5 Th ft h b t] was obtained. Fromelementary analysis and NMR spec- Se or m a e m f 1 area en 0t es trumit was identified to be an alternate copolymer of were sealed and theacrylonltrile and butadiene were allowed to copolymerize at the varioustemperatures listed butadiene and acrylonitrile. The microstructure ofbutadiene units in the alternate copolymer was all trans-conin Table 5for 16 hours. From their elementary analyses figuration. Its glasstransition temperature was observed and. NMR spectra the copolymersprepared in these to e examples were all identified to be alternatecopolymers EXAMPLES 17-19 of butadiene and acrylonitrile. Themicrostructure of the In these examples employing the usual, dry, ai -fbutadiene units in these alternate copolymers was all technique varyingamounts of diluent and 1 molar chrotrans-configuration.

TABLE Monomers 1 DH t Catalysts l Reaction conditions Copolymer uen ANBD n-heptane CrOCla AlR1R1R Temp. Time Yield [n] Example number (ml.)(ml.) (ml.) soln.(ml.) soln. 0.) (hr.) (g.) (dl./g.

4.0 2 1 AlEt; 1 35 16 4.0 1 2 AlEt; 1 35 16 4.0 1 2 AliBua 1 35 16 4.0 03 AlEt: 1 35 18 4.0 4 1 AlEt: 1 30 20 l AN=Acrylonitrile; BD=Liquidbutadiene.

I CrOaClz soln.=1 molar chromium (VI) oxychloride solution in n-heptane;AlRiRaR; soln.=1 molar triethylaluminum or triisobutylaluminmn solutionin toluene.

I [1;]=Intrinsic viscosity in chloroform at 30 0.

EXAMPLE 25 Employing the usual, dry, air-free technique 2 millilitersn-heptane and millimoles chromium (VI) oxychloride were put successivelyinto a 25 milliliter glass bottle at 25 C. Thereafter the bottle washeld in a low temperature bath at 78 C. and 1 millilitertrietliylaluminum solution in toluene (1 molar solution), 3.3milliliters acrylonitrile and 4.0 milliliters liquid butadiene were putsuccessively into the bottle also employing the usual, dry, air-freetechnique at 78 C. Then the bottle was sealed and the acrylonitrile andbutadiene were allowed to copolymerize at 35 C. for 16 hours. 0.38 g.rubbery alternate copolymer of butadiene and acrylonitrile was obtained.

EXAMPLE 26 Employing the usual dry air-free technique 2 millilitersvanadium (V) oxychloride solution in toluene (1 molar solution), 1milliliter triethylaluminum solution in toluene (1 molar solution), 2.6g. acrylonitrile and 3.5 g. C -fraction containing 1.4 g. butadiene (C-fraction composition: butadiene; 39.7, isobutylene; 30.2, butene-l;13.7, trans-butene-2; 6.2, cis-butene-Z; 4.7, butane; 5.0, propylene;0.2 wt. percent) were put successively into a 25 milliliter glass bottleheld in a low temperature bath at 78 C. Thereafter the bottle was sealedand the acrylonitrile and butadiene were allowed to polymerize at 35 C.for 20 hours. 1.30 g. acetone and chloroform soluble alternate copolymerof butadiene and acrylonitrile was obtained. Its intrinsic viscosity was0.3 (dl./ g.) in chloroform at 30 C. and its glass transitiontemperature was observed to be C.

What is claimed is:

1. A bulk or solution polymerization process for preparing a 1:1alternate copolymer of butadiene and acrylonitrile having alternatingbutadiene and acrylonitrile units, all butadiene units being of transconfiguration and having a sole 7.711- peak (NMR) ascribed to themethylene unit of the butadiene unit, by contacting a mixture ofbutadiene and acrylonitrile in liquid phase in the substantial absenceof moisture at a temperature of from about --78 C. to about +40 C. witha catalyst system formed by mixing a metal oxychloride selected from thegroup consisting of vanadium (V) oxychloride and chromium (V-I)oxychloride with a trialkylaluminum compound.

2. A process of claim 1 wherein the molar ratio of trialkylaluminumcompound to said metal oxychloride is lower than 1.5.

3. A process of claim 1 wherein the copolymerization reaction is carriedout in the form of solution polymerization with a diluent selected fromthe group consisting of a hydrocarbon, a chlorinated hydrocarbon and amixture thereof.

4. A process of claim 1 wherein the molar ratio of butadiene toacrylonitrile in the initial monomer composition is within the rangefrom 20:80 to :20.

5. A process of claim 1 wherein the trialkylaluminum compound is definedby the formula AlR R R wherein R R and R are alkylradicals having from 1to 12 carbon atoms.

6. A process of claim 1 wherein said metal oxychloride is mixed with atrialkylaluminum compound in the presence of a diluent selected from thegroup consisting of a hydrocarbon, a chlorinated hydrocarbon and amixture thereof.

7. A process of claim 3 wherein said trialkylaluminum compound isdefined by the formula AlR R R in which R R and R are alkyl radicalshaving from 1 to 12 carbon atoms, the molar ratio of trialkylaluminumcompound to said metal oxychloride is lower than 1.5, and

the molar ratio of butadiene to acrylonitrile in the initial181603811161 composition is within a range of from 20:80 to 8. A processof claim 7 wherein R R and R are either ethyl or i-butyl.

9. A process of claim 8 wherein said metal oxychloride is mixed withsaid trialkylaluminum compound in the presence of a diluent selectedfrom the group consisting of a hydrocarbon, a chlorinated hydrocarbonand a mixture thereof.

References Cited UNITED STATES PATENTS 3,278,503 10/1966 Serniuk 260825FOREIGN PATENTS 1,487,211 5/1967 France 26082.5

OTHER REFERENCES Symposium of Japanese Chemical Fiber Institute, October1968, No. 26, pp. 83-96, Furakawa et al.

Properties of Acrylonitrile-Butadiene Alternate Copolymers, paperpresented at 17th Annual Meeting of Polymers, Japan, May 1968, p. 423,Furakawa et al.

Journal of Polymer Science, vol. B-S, pp. 47-55 (1967), ComplexCopolymerization, Hirooka et al.

JOSEPH L. SCHOFER, Primary Examiner W. F. HAMROCK, Assistant ExaminerUS. Cl. X.R. 26082.5.

